It is known to use check valves to allow fluid flow in one direction, and to prevent flow in the opposite direction. Check valves are widely used in a wide variety of applications, for example in air conditioning systems, for example in aircraft air conditioning systems. Many types of check valves are known. Some check valves include hinged flappers that open in the direction of fluid flow. In such valves, when a fluid pressure exceeds a predetermined valve “cracking pressure”, the flappers of the valve open. Likewise, if significant pressure drops in the upstream fluid are experienced (such that there is a negative pressure differential across the valve), the flapper elements close, preventing flow reversal. Such check valves typically include a pair of flapper elements and frequently employ stop pins or bumpers which restrict movement of the flapper past a predetermined maximum opening angle.
The flapper elements of such prior art flapper valves typically move through large angles, before impacting the stop pin or bumper when the maximum opening angle is reached. Moreover each flapper is relatively large (typically being semi-circular in shape). The impact of the flappers against the stop pin or bumper may therefore be relatively large. Also, since the flappers are relatively large (and therefore relatively massive), the reaction time of the valve may be quite high.
The present disclosure relates to a check valve which a modified flapper arrangement.